it could be a lot of things.

most common would be you need to burp it, then comes thermostat you can tell if it's your thermostat because the engine temp will be warm but the lower radiator hose will be cold. thus coolant is not flowing passed the thermostat

you can tell if it's your heater core if one of the hoses that go into it are hot and the other one is cold. thus there's a restriction blocking the coolant from flowing through the heater core

really the only other problems it could be are water pump which would probably just leak before it wouldn't pump,your fan clutch is bad thus your fan is not spinning fast enough to suck any air through the radiator...you have a restriction in the motor cause some jack ass put stop leak in it, or the first time it overheated you warped the head and blew the headgasket and it's consuming coolant.